This core is an essential component of the research program in its study of neurocognitive aging, providing an Animal Resource that serves each of the individual projects. A major objective of the overall research program is to elucidate the basis of neurocognitive aging in behaviorally characterized healthy aged rats. The overall research program further exploits the feature of individual differences in neurocognitive aging, a phenomenon that is well-documented in humans and captured in the animal model used in this research. The Animal Resource maintains a colony of pathogen-free male Long-Evans rats, which are additionally screened for disability and physiological impairment. All rats in the Animal Resource undergo assessment of cognitive function in a standardized protocol for "place" and "cue" learning in a water maze apparatus. The Animal resource provides analysis of these results to characterize presence/severity of impairment. Additional behavioral testing in this core will occur as specified for individual projects. Material from animals in the resource is then obtained for the projects, in a form appropriate to the methods used in the neurobiological studies (sacrifice/perfusion/dissection). In some instances live animals will be transferred ' from the Resource to projects for further in vivo analysis (i.e., electrophysiological recording) or to provide fresh tissue as needed for in vitro studies. In those cases Core B personnel work with the Administrative Core to obtain health certificates and prepare rats for shipping in an expedited manner. The Animal Resource Core compiles records on animal health, inventory, and analysis of the behavioral assessments, all in an archived form. In addition to providing rodent material for current projects, Core B also banks tissue specimens (dissected brain regions, peripheral organ tissues, blood samples) to be used at a later date by project investigators or outside scientists, This resource sharing activity is managed and coordinated by the Administrative Core (Core A). In an expanded set of objectives in the research program for the next funding cycle, Core B will also provide a resource of non-human primate tissue on young and aged monkeys that have been behaviorally characterized (behavioral studies conducted under the auspices of a separate funding mechanism [unreadable] RO1 AG10606 "Cognitive Function in the Aged Monkey). Thus, as promising results emerge for the rat model that has comprised the major focus of our efforts, we are uniquely positioned to test the generality of these findings in a well-characterized non-human primate model.